如何删除标题后的一行

Question

我无法删除标题后的一行，以下是我的几行：

\documentclass[letterpaper]{article}
\usepackage{lipsum}
\usepackage[T1]{fontenc} 
\usepackage[hmarginratio=1:1,top=32mm,columnsep=20pt]{geometry} 
\usepackage{multicol}
\usepackage{lettrine} 

\usepackage{abstract} 
\renewcommand{\abstractnamefont}{\normalfont\bfseries} 
\renewcommand{\abstracttextfont}{\normalfont\small\itshape} 

\usepackage{titlesec} 
\renewcommand\thesection{\Roman{section}} 
\renewcommand\thesubsection{\Roman{subsection}} 

\usepackage{fancyhdr} 
\pagestyle{fancy} 
\fancyhf{} 
\fancyfoot[R]{\thepage} 
\fancyhead[L]{\small{Volatile organic compounds in human health and disease: an overview}} 

\fancypagestyle{myfirst}
  {
    \fancyhf{}
    \renewcommand\headrulewidth{0pt}
    \fancyfoot[R]{\thepage}
   }
\usepackage{graphicx}
%----------------------------------------------------------------------------------------
%   TITLE SECTION
%----------------------------------------------------------------------------------------

\title{\vspace{-15mm}\fontsize{24pt}{10pt}\selectfont\textbf{Volatile organic compounds in human health and disease: an overview}}

\author{
\large
\textsc{P\'erez-Cort\'es Obed, L\'opez-Ortega Omar, G\'omez-Pozos Heberto,}\\ \textsc{ T.V. K. Karthik}\\[5mm] % Your name
\normalsize Universidad Aut\'onoma del Estado de Hidalgo \\ % Your institution
\normalsize obed\[email protected]% Your email address
% \vspace{-5mm}
}
\date{} 
%----------------------------------------------------------------------------------------

\begin{document}
 \maketitle % Insert title
 \thispagestyle{myfirst} 

 ------------------------------------------------------------------------------------
%   ABSTRACT
%----------------------------------------------------------------------------------------

\begin{abstract}
\noindent \lipsum[1]
\end{abstract}
\vspace{1cm}
%------------------------------------------

Answer 1

您刚刚丢失了一个注释符号（%）：

\documentclass[letterpaper]{article}
\usepackage{lipsum}
\usepackage[T1]{fontenc} 
\usepackage[hmarginratio=1:1,top=32mm,columnsep=20pt]{geometry} 
\usepackage{multicol}
\usepackage{lettrine} 

\usepackage{abstract} 
\renewcommand{\abstractnamefont}{\normalfont\bfseries} 
\renewcommand{\abstracttextfont}{\normalfont\small\itshape} 

\usepackage{titlesec} 
\renewcommand\thesection{\Roman{section}} 
\renewcommand\thesubsection{\Roman{subsection}} 

\usepackage{fancyhdr} 
\pagestyle{fancy} 
\fancyhf{} 
\fancyfoot[R]{\thepage} 
\fancyhead[L]{\small{Volatile organic compounds in human health and disease: an overview}} 

\fancypagestyle{myfirst}
{
    \fancyhf{}
    \renewcommand\headrulewidth{0pt}
    \fancyfoot[R]{\thepage}
}
\usepackage{graphicx}
%----------------------------------------------------------------------------------------
%   TITLE SECTION
%----------------------------------------------------------------------------------------

\title{\vspace{-15mm}\fontsize{24pt}{10pt}\selectfont\textbf{Volatile organic compounds in human health and disease: an overview}}

\author{
    \large
    \textsc{P\'erez-Cort\'es Obed, L\'opez-Ortega Omar, G\'omez-Pozos Heberto,}\\ \textsc{ T.V. K. Karthik}\\[5mm] % Your name
    \normalsize Universidad Aut\'onoma del Estado de Hidalgo \\ % Your institution
    \normalsize obed\[email protected]% Your email address
    % \vspace{-5mm}
}
\date{} 
%----------------------------------------------------------------------------------------

\begin{document}
    \maketitle % Insert title
    \thispagestyle{myfirst} 

    %------------------------------------------------------------------------------------
    %   ABSTRACT
    %----------------------------------------------------------------------------------------

    \begin{abstract}
        \noindent \lipsum[1]
    \end{abstract}
    \vspace{1cm}
    %------------------------------------------
\end{document}

得出：